By default, Veeam Backup & Replication uses its proprietary file indexing mechanism to index VM guest OS files and let you search for them in backups with Veeam Backup Enterprise Manager. Using Veeam's proprietary mechanism is the best practice. However, you have an option to engage the Veeam Backup Search component and Microsoft Search Server in the indexing process.
To use Veeam Backup Search, you should install the Veeam Backup Search component from the installation package on a machine running Microsoft Search Server. The Veeam Backup Search server runs the MOSS Integration Service that invokes updates of index databases on Microsoft Search Server. The service also sends search queries to Microsoft Search Server which processes them and returns necessary search results to Veeam Backup Enterprise Manager.
For more information, see Using Veeam Backup Search (Optional Component).